Notes for disconnecting and connecting the vehicle battery (M4 2021-2023)
Observe safety instructions for handling vehicle battery. Refer to NOTES REGARDING THE LITHIUM ION BATTERY (M4 2021-2023) .
Before disconnecting vehicle battery:
Turn off the ignition and other electrical loads/consumers to prevent spark formation when reconnecting.
Attention!
- There is a danger of mixing up battery cables: if the positive battery cable and battery ground lead are the same color and you are in doubt, follow the polarity to the vehicle battery, then mark and cover the leads
- The on-board computer and clock may lose your data.
General notes on disconnecting the vehicle battery:
- Do not disconnect battery leads and leads from alternator and starter motor while engine is running.
- Disconnect terminal of battery ground lead from the battery. Cover battery negative terminal(s) and secure.
- Disconnect both battery ground leads in version with auxiliary battery. Cover battery negative terminal(s) and secure.
- When work is carried out on the electrical system, faults may be caused in the fault memories of some control units when the vehicle battery is connected.
Only lead AGM battery:
- On vehicles with IBS at negative battery terminal:
Do not under any circumstances detach/lever off terminal covers by force.
Do not under any circumstances release the hexagon socket screw of the IBS.
Note the following after having connected the vehicle battery:
Attention!
The scope of application of some systems may be restricted after an open circuit.
Personal Profiles may also be lost.
Settings or activations must be carried out, depending on the equipment specification.
For example:
- Activate sliding/tilting sunroof, if necessary
- Activate power window, if necessary
Refer to the diagnostic system for further vehicle-specific information.